After spotting something important, your brain has a brief "blind spot" of 200-500ms where it misses the next thing. Watch for TWO red letters in the stream. You'll likely catch the first but miss the second—your attention literally blinks.
Watch for two RED letters in the stream of black letters. Enter what you saw:
The attentional blink typically peaks at 200-300ms (2-3 items) after the first target. Your brain is processing T1 and literally cannot see T2.